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Grade 9 · Math · Unit 11 of 11

Probability in Society

Chance, fair games, forecasts and risk.

What your child practises

Practises how probability is used in everyday life: forecasts, fair games and expected value, insurance, independent events and experimental versus theoretical probability.

Manitoba Curriculum learning outcome: 9.SP.4 · the role of probability in society

How we explain it

Children can open this short lesson before they practise.

  1. Probability helps people make choices, like insurance, weather and games.
  2. Probability = favourable ÷ possible outcomes.
  3. A small chance is not impossible.

Example: The chance of rain is 30%. What is the chance of no rain? The two chances add to 100%. 100 − 30 = 70. Answer: 70%

Sample questions

A taste of this unit. In the app, questions change every time and get easier or harder to match your child.

  1. Question 1

    Flipping a coin 10 times gives 7 heads. What is this result called?

    • a sample space
    • the theoretical probability
    • an experimental result

  2. Question 2

    A coin lands heads five times in a row. What is the chance of heads on the next flip?

    • less than 1/2
    • 1/2
    • more than 1/2

  3. Question 3

    As you repeat an experiment many more times, the experimental probability usually gets…

    • equal to zero
    • further from it
    • closer to the theoretical probability

  4. Question 4

    Why do insurance companies use probability?

    • to avoid paying anyone
    • to estimate how often claims will happen so they can set prices
    • to decide which houses will burn

  5. Question 5

    A probability of 0 means the event is…

    • unlikely
    • impossible
    • certain

  6. Question 6

    In the raffle above, a ticket costs $2 and is worth $1 on average. Over many tickets, a player will…

    • lose money on average
    • win money on average
    • break even exactly

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